This invention relates to spring contact probes in general and particularly to such probes that are used in fixture interfaces for use in applications requiring particularly robust design.
Spring probes for electrical interfaces are well known in the prior art and represent a wide family of technology for providing interconnection between electrical contact points. Some spring probes are designed for circuit testing and are suited for placing in a matrix providing an interface between a testing circuit computer and a device under test, which is ordinarily an integrated chip or a circuit board. While some circuit boards are loaded with components and then tested when completed, a preferred method of manufacture is to test circuit boards and if passed, then stuff the board with the necessary components to create the full circuit, as this procedure is much more cost effective if the circuit board is defective. Other spring probes are used in interfaces when components may be removed and replaced, as necessary for maintenance or control unit upgrades.
A major criterion for spring probes is that they provide the shortest possible circuit path between test sites in order to minimize resistance losses. Yet another criterion for spring probes which are used in harsh environments is that they be designed for robustness. Vehicles and weapons guidance and control systems use electrical circuits in which key components are removed and replaced, often for testing purposes or for upgrades. These units are commonly subjected to extreme heat, pressure, g-forces and vibrations and must maintain electrical contacts between components for functionality.
An electrical contact interface includes a spring probe which fits into intermediate structure for positioning between circuit contacts. The spring probe consists of a pair of oppositely extending plungers with each plunger including a head end having a contact tip, an inner shoulder and a rearwardly extending shaft terminating in a lug end. A coil spring is sleeved about the plungers and positioned between the opposite inner shoulders with the shafts extending toward each other and in constant sliding engagement with each other through the lug ends. The lug ends slide back and forth as the shafts mutually reciprocate and abut each other at an extreme travel relation of the plungers to prevent mutual disengagement of the plungers from within the coil spring. The coil spring and opposed plungers form a unit which is placed within the intermediate interconnect structure, such as within a bore extending between opposite side surfaces of an interconnect fixture.
The objects of the present invention are:
a) to provide an electrical contact spring probe which fits into an intermediate structure for positioning between circuit contacts;
b) to provide such a spring probe which is double ended to provide resilient contact tips on opposite ends;
c) to provide such a spring probe which is particularly robust in construction;
d) to provide such a spring probe which provides an electrical circuit path of minimal length to minimize resistance; and
e) to provide such a spring probe and interface device which is particularly well adapted for the intended purpose and is economical of construction.
Other objects and advantages of the present invention will become apparent from the following description taken in connection with the drawings which provide an exemplary embodiment of the present invention.